1. Field of the Invention
The present invention relates to a fuel supplying system of a gas-engine and more particularly to a fuel supplying system of a gas-engine of a lean-burn type.
2. Description of the Related Art
A conventional fuel supplying system of a gas-engine, as shown in FIG. 9, is disclosed in Japanese Utility Model Laid-open Print No. 58(1983)-142357 published without examination, wherein fuel for gas-engine 101 is composed of a mixture of gas and air. Gas and air are mixed in mixer 102. Governor 105 and bypass passage 106 are located on fuel passage 104. Valve 107 is located on bypass passage 106. Gas in gas-tank 103 is enclosed at a high pressure. However, the pressure of the gas is reduced to atmospheric pressure in governor 105. Air is supplied to mixer 102 from air-cleaner 108 via air passage 109.
Starter 110 starts gas-engine 101. When switch 111 is turned on, valve 107 opens, and starter 110 is activated.
Gas-engine 101 is a lean-burn type engine which exhausts a small amount of NOx (Nitrogen Oxide). Therefore, the quantity of gas is very small compared to the quantity of air. Gas-engine 101 has the disadvantageous characteristic of bad starting capacity. For good starting capacity of gas-engine 101, the quantity of gas is increased by opening valve 107.
However, the gas supplied via valve 107 is at a high pressure, namely, it is not reduced to atmospheric pressure. When gas-engine 101 is started, the flowing gas is at two different pressures: the atmospheric pressure and the high pressure of gas-tank 103. Therefore, it is difficult to control gas-engine 101.